Integrated circuits devices are used in many applications including portable electronic products, such as cell phone, portable computers, voice recorders, etc. as well as in many larger systems with electronic components, such as cars, planes, industrial control systems, etc. Across virtually all these applications, there continues to be a continuous, strong demand for increasing features while reducing the area required for the electronic devices or components. The intense demand is no more visible than in the portable electronic devices and products that have become so commonplace in everyday life.
In the manufacture of integrated circuit devices, it is necessary to provide many electrically conductive contacts and interconnect layers in order to connect electrically various parts of the device to each other and to external circuitry. As manufacturers of integrated circuit devices have continued their efforts in attempts to meet the needs of further reductions in the size of the devices, many have attempted to improve density, such as by reducing the size of the electrical contacts as well as the interconnect pitch and dimensions. Reducing the size of electrical contacts, interconnect size and dimensions must be accomplished without reducing the reliability of the devices as well as keeping the surface planar so that subsequent interconnect layers can be formed.
Conventional methods of depositing metal contacts, such as by sputtering, have great difficulty in depositing enough material into the contact holes in order to form reliable electrical connections between semiconductor layers and the metal contact. In addition, the resulting topology is non-planar and can place severe constraints on the complexity of the interconnect layers. This method of manufacturing has the limitation that the contact hole must be wide enough and have the correct profile to allow a limited amount of metal to enter the contact hole to form the contact. The obtainable reduction in size of the contact hole is limited by the step coverage capability of conventional sputtering systems.
The aspect ratio of the electrical contacts, such as a through-hole or window, for connecting upper-layer and lower-layer semiconductors formed on a substrate is increased as the integrated circuit devices are further refined and more densely integrated. This increases the difficulty of depositing sufficient metal to enter the contact hole forming the contact between semiconductor layers. Some attempts to provide the electrical connections include embedding a plug in the electrical contacts having a high aspect ratio. Many attempts suffer from poor performance, high rates of defects, and difficulty controlling production processes.
Tungsten contact shorting is one such problem that results in all of these issues. Lateral etching of the contact opening may be caused by an incorrectly mixed initial layer. The incorrect mixture may be caused by injector valve clogging or an initial outburst of one of the materials to be deposited. The incorrect mixture creates an interface area where the chemical bonds are weaker and easier to break. Etching then processes at a higher rate providing a region for the tungsten contact to penetrate laterally. The lateral penetration results in poor performance, high rates of defects, difficulty controlling production processes and shorting.
Thus, a need still remains for an integrated circuit system with contact film to provide increasing density without sacrificing reliability, performance, yield, and high volume manufacturability. In view of the increasing demand for continued density improvements in electronic components and systems, particularly portable electronic products, it is increasingly critical that answers be found to these problems.
Solutions to these problems have been long sought but prior developments have not taught or suggested any solutions and, thus, solutions to these problems have long eluded those skilled in the art.